21150205423405 has 16 divisors (see below), whose sum is σ = 26723755183680. Its totient is φ = 16025005636992.

The previous prime is 21150205423313. The next prime is 21150205423409. The reversal of 21150205423405 is 50432450205112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21150205423405 - 2²⁷ = 21150071205677 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21150205423409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31778184 + ... + 32436913.

It is an arithmetic number, because the mean of its divisors is an integer number (1670234698980).

Almost surely, 2^{21150205423405} is an apocalyptic number.

It is an amenable number.

21150205423405 is a deficient number, since it is larger than the sum of its proper divisors (5573549760275).

21150205423405 is a wasteful number, since it uses less digits than its factorization.

21150205423405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64218588.

The product of its (nonzero) digits is 48000, while the sum is 34.

Adding to 21150205423405 its reverse (50432450205112), we get a palindrome (71582655628517).

The spelling of 21150205423405 in words is "twenty-one trillion, one hundred fifty billion, two hundred five million, four hundred twenty-three thousand, four hundred five".